In a process of manufacturing a semiconductor device, the semiconductor devices are being recently further miniaturized, and the importance of pattern dimension management for process management has been increased. In recent years, the pattern is formed to have a three-dimensional structure, and thus, a manufacturing method of integrating the pattern has been applied. In order to manage the dimension of the pattern having the three-dimensional structure, it is necessary to evaluate performance of the pattern in a sectional direction. In order to evaluate the section of the pattern, it is considered that a sample is cut and the section of the pattern seen on a fracture surface is observed. A method in which a surface on which a section of the sample in a longitudinal direction is exposed is formed in the direction perpendicular to the sample surface by drilling the sample in a direction perpendicular to the sample surface without cutting the sample and the section thereof is evaluated is considered.
In PTL 1, a method in which a sample thickness t is calculated by forming a taper-shaped inclined surface by a focused ion beam (FIB), acquiring a surface observed image of the formed inclined surface by using an electron microscope, and calculating 2·X·tan α based on a scanning distance X of an electron line and an inclination angle α of the inclined surface has been described.
In PTL 2, an observation method of observing unevenness of the sample surface by drawing a straight line by using an ion beam is a portion in which the unevenness of the sample surface is desired to be observed and acquiring an image of the portion drawn from the straight line.